Hermetically closed tank

A tank that: – is not equipped with safety valves, bursting discs, other similar safety devices or vacuum valves or selfoperating ventilation valves; or – is equipped with safety valves preceded by a bursting disc according to 6.8.2.2.10, but is not equipped with vacuum valves or self-operating ventilation valves. A tank intended for the carriage of liquid substances with a calculation pressure of at least 4 bar or intended for the carriage of solid substances (powdery or granular) regardless of its calculation pressure is also considered hermetically closed if it: – is equipped with safety valves preceded by a bursting disc according to 6.8.2.2.10 and vacuum valves or self-operating ventilation valves, in accordance with the requirements of 6.8.2.2.3; or, – is not equipped with safety valves, bursting discs or other similar safety devices, but is equipped with vacuum valves or self-operating ventilation valves, in accordance with the requirements of 6.8.2.2.3.